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Subject[PATCH 5/7 v2] dma: sh: use an integer slave ID to improve API compatibility
Date
Initially struct shdma_slave has been introduced with the only member - an
unsigned slave ID - to describe common properties of DMA slaves in an
extensible way. However, experience shows, that a slave ID is indeed the
only parameter, needed to identify DMA slaves. This is also, what is used
by the core dmaengine API in struct dma_slave_config. We switch to using
the slave_id directly, instead of passing a pointer to struct shdma_slave
to improve compatibility with the core. We also make the slave_id signed
for easier error checking.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
drivers/dma/sh/shdma-base.c | 25 +++++++++++++------------
drivers/dma/sh/shdma.c | 12 ++++++------
include/linux/sh_dma.h | 8 ++++----
include/linux/shdma-base.h | 8 ++++----
4 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
index f75ebfa..73db282 100644
--- a/drivers/dma/sh/shdma-base.c
+++ b/drivers/dma/sh/shdma-base.c
@@ -76,7 +76,6 @@ static dma_cookie_t shdma_tx_submit(struct dma_async_tx_descriptor *tx)
container_of(tx, struct shdma_desc, async_tx),
*last = desc;
struct shdma_chan *schan = to_shdma_chan(tx->chan);
- struct shdma_slave *slave = schan->slave;
dma_async_tx_callback callback = tx->callback;
dma_cookie_t cookie;
bool power_up;
@@ -138,7 +137,7 @@ static dma_cookie_t shdma_tx_submit(struct dma_async_tx_descriptor *tx)
* Make it int then, on error remove chunks from the
* queue again
*/
- ops->setup_xfer(schan, slave);
+ ops->setup_xfer(schan, schan->slave_id);

if (schan->pm_state == SHDMA_PM_PENDING)
shdma_chan_xfer_ld_queue(schan);
@@ -186,7 +185,7 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan)
* never runs concurrently with itself or free_chan_resources.
*/
if (slave) {
- if (slave->slave_id >= slave_num) {
+ if (slave->slave_id < 0 || slave->slave_id >= slave_num) {
ret = -EINVAL;
goto evalid;
}
@@ -196,9 +195,13 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan)
goto etestused;
}

- ret = ops->set_slave(schan, slave);
+ ret = ops->set_slave(schan, slave->slave_id);
if (ret < 0)
goto esetslave;
+
+ schan->slave_id = slave->slave_id;
+ } else {
+ schan->slave_id = -EINVAL;
}

schan->desc = kcalloc(NR_DESCS_PER_CHANNEL,
@@ -208,7 +211,6 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan)
goto edescalloc;
}
schan->desc_num = NR_DESCS_PER_CHANNEL;
- schan->slave = slave;

for (i = 0; i < NR_DESCS_PER_CHANNEL; i++) {
desc = ops->embedded_desc(schan->desc, i);
@@ -366,10 +368,9 @@ static void shdma_free_chan_resources(struct dma_chan *chan)
if (!list_empty(&schan->ld_queue))
shdma_chan_ld_cleanup(schan, true);

- if (schan->slave) {
+ if (schan->slave_id >= 0) {
/* The caller is holding dma_list_mutex */
- struct shdma_slave *slave = schan->slave;
- clear_bit(slave->slave_id, shdma_slave_used);
+ clear_bit(schan->slave_id, shdma_slave_used);
chan->private = NULL;
}

@@ -559,7 +560,7 @@ static struct dma_async_tx_descriptor *shdma_prep_slave_sg(
struct shdma_chan *schan = to_shdma_chan(chan);
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
- struct shdma_slave *slave = schan->slave;
+ int slave_id = schan->slave_id;
dma_addr_t slave_addr;

if (!chan)
@@ -568,9 +569,9 @@ static struct dma_async_tx_descriptor *shdma_prep_slave_sg(
BUG_ON(!schan->desc_num);

/* Someone calling slave DMA on a generic channel? */
- if (!slave || !sg_len) {
- dev_warn(schan->dev, "%s: bad parameter: %p, %d, %d\n",
- __func__, slave, sg_len, slave ? slave->slave_id : -1);
+ if (slave_id < 0 || !sg_len) {
+ dev_warn(schan->dev, "%s: bad parameter: len=%d, id=%d\n",
+ __func__, sg_len, slave_id);
return NULL;
}

diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c
index 9f0a2e5..9a10d8b 100644
--- a/drivers/dma/sh/shdma.c
+++ b/drivers/dma/sh/shdma.c
@@ -285,12 +285,12 @@ static bool sh_dmae_channel_busy(struct shdma_chan *schan)
}

static void sh_dmae_setup_xfer(struct shdma_chan *schan,
- struct shdma_slave *sslave)
+ int slave_id)
{
struct sh_dmae_chan *sh_chan = container_of(schan, struct sh_dmae_chan,
shdma_chan);

- if (sslave) {
+ if (slave_id >= 0) {
const struct sh_dmae_slave_config *cfg =
sh_chan->config;

@@ -302,7 +302,7 @@ static void sh_dmae_setup_xfer(struct shdma_chan *schan,
}

static const struct sh_dmae_slave_config *dmae_find_slave(
- struct sh_dmae_chan *sh_chan, unsigned int slave_id)
+ struct sh_dmae_chan *sh_chan, int slave_id)
{
struct sh_dmae_device *shdev = to_sh_dev(sh_chan);
struct sh_dmae_pdata *pdata = shdev->pdata;
@@ -320,11 +320,11 @@ static const struct sh_dmae_slave_config *dmae_find_slave(
}

static int sh_dmae_set_slave(struct shdma_chan *schan,
- struct shdma_slave *sslave)
+ int slave_id)
{
struct sh_dmae_chan *sh_chan = container_of(schan, struct sh_dmae_chan,
shdma_chan);
- const struct sh_dmae_slave_config *cfg = dmae_find_slave(sh_chan, sslave->slave_id);
+ const struct sh_dmae_slave_config *cfg = dmae_find_slave(sh_chan, slave_id);
if (!cfg)
return -ENODEV;

@@ -579,7 +579,7 @@ static int sh_dmae_resume(struct device *dev)
if (!sh_chan->shdma_chan.desc_num)
continue;

- if (sh_chan->shdma_chan.slave) {
+ if (sh_chan->shdma_chan.slave_id >= 0) {
const struct sh_dmae_slave_config *cfg = sh_chan->config;
dmae_set_dmars(sh_chan, cfg->mid_rid);
dmae_set_chcr(sh_chan, cfg->chcr);
diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h
index a79f10a..4e83f3e 100644
--- a/include/linux/sh_dma.h
+++ b/include/linux/sh_dma.h
@@ -27,10 +27,10 @@ struct sh_dmae_slave {
* a certain peripheral
*/
struct sh_dmae_slave_config {
- unsigned int slave_id;
- dma_addr_t addr;
- u32 chcr;
- char mid_rid;
+ int slave_id;
+ dma_addr_t addr;
+ u32 chcr;
+ char mid_rid;
};

struct sh_dmae_channel {
diff --git a/include/linux/shdma-base.h b/include/linux/shdma-base.h
index c3a19e9..6263ad2 100644
--- a/include/linux/shdma-base.h
+++ b/include/linux/shdma-base.h
@@ -43,7 +43,7 @@ struct device;
*/

struct shdma_slave {
- unsigned int slave_id;
+ int slave_id;
};

struct shdma_desc {
@@ -66,7 +66,7 @@ struct shdma_chan {
size_t max_xfer_len; /* max transfer length */
int id; /* Raw id of this channel */
int irq; /* Channel IRQ */
- struct shdma_slave *slave; /* Client data for slave DMA */
+ int slave_id; /* Client ID for slave DMA */
enum shdma_pm_state pm_state;
};

@@ -93,8 +93,8 @@ struct shdma_ops {
dma_addr_t (*slave_addr)(struct shdma_chan *);
int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,
dma_addr_t, dma_addr_t, size_t *);
- int (*set_slave)(struct shdma_chan *, struct shdma_slave *);
- void (*setup_xfer)(struct shdma_chan *, struct shdma_slave *);
+ int (*set_slave)(struct shdma_chan *, int);
+ void (*setup_xfer)(struct shdma_chan *, int);
void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);
struct shdma_desc *(*embedded_desc)(void *, int);
bool (*chan_irq)(struct shdma_chan *, int);
--
1.7.2.5


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